Re: [Valgrind-users] Best valgrind options for finding corrupt memory

[Philippe W. <phi...@sk...>]

On Tue, 2014-01-14 at 17:04 +0100, David Faure wrote:
> On Tuesday 14 January 2014 08:03:14 Samuel Quiring wrote:
> > Greetings,
> > 
> > I suspect my program is corrupting (overwriting) memory, e.g., malloc'ing 16
> > bytes for a string that is 17 bytes when you count the nul, then copying 17
> > bytes into the 16 byte area.  What are the best valgrind options for
> > detecting memory corruption?
> 
> The default options :-)
> 
> (memcheck tool)
> 
memcheck default options are effectively ok by default.

But there are some options that you can change if you want to increase
the probability to find a memory corruption or get more info about 
such a bug.

Typically, you might use one or more of the following:

    --redzone-size=<number>   set minimum size of redzones added before/after
                              heap blocks (in bytes). [16]

    --read-var-info=yes|no    read debug info on stack and global variables
                              and use it to print better error messages in
                              tools that make use of it (Memcheck, Helgrind,
                              DRD) [no]
    --freelist-vol=<number>          volume of freed blocks queue     [20000000]
    --freelist-big-blocks=<number>   releases first blocks with size>= [1000000]
    --keep-stacktraces=alloc|free|alloc-and-free|alloc-then-free|none
        stack trace(s) to keep for malloc'd/free'd areas       [alloc-then-free]

The above will impact (increase or decrease) memory and/or cpu used by valgrind.


Philippe